In recent years, polymers containing an organosiloxane substituted methacrylate such as tris(trimethylsiloxy)silylpropyl methacrylate or a modified polysiloxane as a component have been developed and used as materials for contact lenses with high oxygen permeability (JP-A-85-142324 and JP-A-79-24047).
However, due to the hydrophobic nature of the siloxane constituent, these materials tend to exhibit repellency of lachrymal tears on the surface and to result in clouding of the lenses.
Furthermore, as a result of the low inter-molecular interaction peculiar to the silicone constituent, they show poor creep characteristics and low impact strength as physical disadvantages.
Moreover, when the copolymerization of comonomers consisting of a hydrophilic monomer with active hydrogen such as 2-hydroxyethyl methacrylate and the silicone monomers is carried out in order to modify the lens material by polymer reaction or to improve the hydrophilic property of the polymer, then the further disadvantage arises that the electrostatic repulsion between hydroxyl groups as polar groups and siloxane portions as non-polar groups causes phase separation, not allowing a transparent polymer to be obtained.